Duplicating method



Patented Mar. 10, 1931 UNITED STATES WILHELH RITZERFELD, F BERLIN, GERMANY DUPLICATING METHOD 1T0 Drawing. Application. filed November 13, 1929, Serial No. 406,980, and in. Germany October 17, 1929.

In my prior Patent No. 1,645,930 I have described a method of duplicating printed or written matter, drawings, addresses, etc. from originals furnished with reverse char- 5 acters, signs or the like on sheets of paper, cards, envelopes or other suitable surfaces, the sheets, cards, etc. being previousl moistened with a readily volatilizing liqui and it is a particular feature of the said method that both for the original as well as the copy sheets ordinary paper or pasteboard usually obtainable on the market may be employed, i. e., particular importance not being attached to special ualities.

In continuation of this method I have discovered various improvements in association therewith permitting the said method to be utilized to an extent representing a multiple of its previous use.

The improvement in question covers all three of the main features constituting the said method, viz., the material used for the originals, the material employed for the copy paper, and the colorless and readily volatiliz- ,5 in liquid.

In employing the materials hitherto in use, i. e., ordinary original and copy paper and a volatilizing liquid consisting of methylated spirits, ether, etc., it has been fpossible only 30 to obtain a limited number 0 copies, say, between 80 and 100, this for the following reasons:

(1) The ink on the original serving to make the copies from the reverse characters on the latter on to the copy paper is liable to combine with the original or remain adhering thereto;

(2) The copy paper shewed the tendency to take up too much moisture and also too much ink, so that the copies were not sharp,

and

(3) The liquid for dissolving the ink removed too much ink from the original, also causing the copies to be unsharp.

To overcome these drawbacks and to enable a larger number of copies to be obtained from the one original a large number of tests and experiments have been made, and in carrying the invention into effect I now proceed as follows:

Special papers or cards are employed both for the production of the original as well as the copy paper, and as volatilizing liquid I have ascertained that a mixture is to be preferred, the composition of which will be described at a later point.

In producing the original a not too thin but very soft paper is employed having a smooth and dense surface, for example socalled art or chromo paper, or a paper containing a large amount of chalk. When furnishing this paper with the reverse characters, immaterial of the fact as to whether the same are applied by hand or by machine, these characters are impressed more into the paper and on to the back thereof, so that greatly raised characters are formed as if the same were embossed, these representing the reversed image to be transferred to the copy paper. It has been found that even papers of very considerable thickness, such for example as greatly employed in making address stencils, also possess the same admirable properties referred to above.

In adopting the method referred to there is obtained what might be compared with a printing plate having raised characters, the only difference being that in this case the plate is furnished during'the production with the necessary color for producing the copies by placing behind the plate a colour sheet having the colour side turned inwardly. Since a paper having a smooth and dense surface is employed, the color is unable to penetrate into the structure thereof but merely remains adhering to the surface, so that the same may be utilized practically in its entirety for reproduction purposes.

A further important advantage associated with the invention consists in the elimination of one considerable drawback experienced when using paper of the ordinary kind, i. e., when producing the original for example by means of a typewriter the impression of the keys, and this applies more particularly to certain closed letters, such as the letter 0, is distributed to a better degree over the surface even when the keys are struck sharply in the manner really required, and the letter is not simply cut out of the paper such as frequently occurs when employing paper of the ordinary kind. If producing the stencil by a hand it may also occur that when using a hard point the original is cut if using the ordinary kind of paper. This, however, is completely avoided when using a strong, soft and yielding paper of the kind referred to.

An additional advantage is also obtained by the use of a fairly thick paper resembling pasteboard. When using address stencils, which are frequently required but perhaps at long intervals, a drawback will be found to exist in the fact that due to insufiicient thickness of the paper the stencils do not readily adapt themselves to filing purposes, so that some difficulty is experienced in tracing a certain address stencil without undue loss of time. Due to the thickness of the paper employed according to the invention the stencils really constitute cards, which may therefore be filed in trays or cabinets in a manner enabling any particular address card or stencil to be traced immediately without difficulty.

For the reproduction itself, that is to say-- as copy paper, a'half matt paper is employed containing little wood and not entirely White but tending more towards a yellowish color, a'

paper not allowing the passage of light and sometimes termed a machine smoothed paper. This paper has the peculiarity of producing much cleaner and sharper copies Without absorb-ing too much or too little liquid for dissolving the ink. Since also in this case the ink or color does not penetrate into the paper only sufiicient color is taken up as is necessary for obtaining a sharp and exact copy, naturally resulting in a correspondingly increased number of reproductions.

' The use of a dissolving liquid for the ink made up from diflerent substances has also proved to offer considerable advantages. After considerable experiment it has been ascertained that a mixture consisting of palatinol, benzole, ethyl-glycol, methylated spirits, toluol and glycerine is to be preferred. Naturally it is also possible in place of any one of these liquids to employ another one having in the combination the same effect on the ink or color to be dissolved. For example, in place of ethyl-glycol it is possible to employ benzyl alcohol or the solvent known in the trade as G. C. solvent.

This mixture has the surprising action of dissolving only a minimum of color or ink from the original, but nevertheless enabling a sharp and entirely clear impression to be obtained. It also has the property of not penetrating or at the most only to very little extent into the copy paper, and it will be found that when using this mixture roughly three times the number of useful copies may be obtained.

With these additional features of the new method employed in combination it has been ascertained that more than five times the number of useful reproductions are obtainable,

that is to say-roughly about 500 copies from the one original.

It is of course understood that various modifications are quite possible within the meaning of the above and the appended claims without departing from the spirit of the invention.

What I claim as new and desire to secure by Letters Patent is:

1. A method of duplicating printed or written matter, drawings, addresses and the like by reproduction from originals furnished with reverse characters, etc., on to sheets of paper, cards, envelopes, etc. previousl moistened with a rapidly volatilizing liqui consisting in making the original stencil on a sheet of paper which is relatively thick, very soft, and possesses a smooth and dense surface, for example a paper containing chalk, so that upon producing the stencil the characters, etc. are impressed deeply into the paper and on to the back thereof forming strongly raised reversed characters on the back, applying. the color for reproduction purposes to the raised portions as the latter are being produced, and making copies from the stencil thus obtained on to previously moistened copy sheets.

2. A method of duplicating printed or written matter, drawings, addresses and the like by reproduction from originals furnished with reverse characters, etc., on to sheets of paper, cards, envelopes, etc. pre viously moistened with a rapidly volatilizing liquid, consisting in making the original stencil on a sheet of paper which is relatively thick, very soft and possesses a smooth and dense surface, so that the characters are impressed deeply into the paper and on to the back thereof forming strongly raised reversed characters on the back, applying the color for reproduction purposes to the raised portions as the latter are being produced, and making copies from the stencil thus obtained on to previously moistened copy sheets consisting of a half matt, yellowish paper containing little wood and having the pro erty of absorbing only very little of the liquid employed for moistening purposes.

3. A method of duplicating printed or written matter, drawings, addresses and the like by reproduction from originals furnished with reverse characters, etc., on to sheets of paper, cards, envelopes, etc. previously moistened with a rapidly volatilizing liquid, consisting in making the original stencil on a sheet of paper which is relatively thick, very soft and possesses a smooth and dense surface, so that the characters are impressed deeply into the paper and on to the back thereof forming strongly raised reversed characters on the back, applying the color for reproduction purposes to the raised portions as the latter are being produced, and making copies from the stencil thus produced on to copy sheets previously moistened with a mixture consisting of palatinol, benzole, ethyl-glycol, methylated spirits, toluol and glycerine or other equivalent liquids.

4. A method of duplicating printed or Written matter, drawings, addresses and the like by reproduction from originals furnished with reverse characters, etc., on to sheets of paper, cards, envelopes, etc. pre viously moistened with a rapidly volatilizing liquid, consisting in making the original stenoil on a sheet of paper which is relatively thick, very soft, and possesses a smooth and dense surface, for example a paper containing chalk, so that upon producing the stencil the characters, etc. are impressed deeply into the paper and on to the back thereof forming strongly raised reversed characters on the back, applying the color for reproduction purposes to the raised portions as the latter are being produced, and making copies from the stencil thus obtained on to copy sheets consisting of a half-matt, yellowish paper containing little wood, the said copy sheets being previously moistened with a mixture consisting of palatinol, benzole, ethyl-glycol, methylated spirits, toluol and glycerme, whereby the said copy sheets possess the property of absorbing only very little of the said mixture.

In testimony whereof I have afixed my signature.

WILHELM RITZERFELD. 

